28 University of California Publications in Agricultural Sciences [Vol. 3 



figure 1. While, however, the measurements show clearly enough the 

 effects of the different soil moisture percentages on the growth of 

 the young lemon trees, they do not really tell the whole story, since 

 the general vigor and abundance of foliage are naturally as much and 

 perhaps more affected than the height by the moisture conditions in 

 the soil. For that reason photographs taken at about the time the 

 measurements were made are submitted herewith to show the actual 

 condition of the trees. 



By whatever criterion the results are gauged, it is at once clear 

 that the effects of the soil moisture content on the development of 

 the young lemon trees are most striking. For the soil and plant in 

 question, 20 per cent of moisture based on the dry weight of the soil 

 seems to be optimum in so far as the total growth and the height of 



5 S 



~ZZ 2? TS~ 



Fig. 1. Showing the relative heights of lemon trees grown with different 

 quantities of moisture. Trees 29 months old; in experiment 17 months. The 

 relative heights are shown on the ordinates and the percentages of moisture under 

 which they were produced are given in the abscissae. The broken line shows the 

 height of all the trees at the beginning of the experiment. 



the trees are concerned. A fact which is not brought out by either 

 the measurements or the photographs is that the general tone and 

 color of the trees growing in the 20 per cent cylinders is somewhat 

 inferior to that of the trees growing in the 16 per cent and 18 per cent 

 cylinders. The optimum moisture content of the loam studied for 

 young Lisbon lemons seems to be therefore between 18 and 20 per 

 cent, if we may judge from the experiment described and from the 

 time given it. The trees at or near the optimum moisture content 

 doubled in height and general size during the period mentioned, while 

 the trees at 10 per cent or at 30 per cent moisture contents have 

 scarcely gained more than half of their original height in the period 

 named. 



Other important points deserve mention in connection with the 

 results obtained. It appears from the data given that the range of 



